One of the companies that made exhaust for detroit started with rolls of flat stock, thru the roller dies and welders, QC was automated, then straight towards the auto bender but there was about a 100 ft space and the pipe was flexed into a 5 story loop that varried in height as the pipe went into the rotary bender at varing speed as it was bent. one big continuous operation. like the video, It used a rotary bender